Water soluble colour salts



' from 3-amino pyridine.

WATER SOLUBLE COLOUR SALTS 'Werner Bossard, Riehen near'Basel, and Jacques Voltz and Frangois Favre, Basel, Switzerland, assignors to J. R. Geigy, A.-G., Basel, Switzerland, a Swiss'firm No Drawing. ApplicationJauuary 23, 1956 Serial No. 560,872

Claims priority, application Switzerland January 28, 1955 8 Claims. (Cl. 260-146) The invention concerns water soluble colour salts which -contain'an azo dyestuif as cationand processes for the production thereof from azo dyestuffs which are insoluble in water and which contain apyridine ring.

.:It has been found that stable water soluble colour salts which contain the azo dyestutf as cation are obtained if an azo dyestuff, having no acid dissociating, salt form- :ing groups, of the general formula:

wherein A represents a mono 'or poly nuclear pyridine ring system which is bound to the azo group by a carbon atom of the pyridine ring, and wherein B represents the radical of an azo component which may be modified in the dye'stulf molecule, is reacted at a raised temperature "with suitable alkylating agents.

The pyridine ring in A, can be fused witha benzene ring to form a quinoline ring and these ring systems "can be further substituted as desired within the bounds of the definition, 'e. g. by alkyl, alkoxy, aralkyl,'aryl, .nitro, acylamino, carboxylic acid ester groups or by halogen. B can represent the radical of a coupling component further substituted as desired within the bounds;

of the definition, in particular in the azo dyestuffs derived However, the term azo component should not have a limited meaning in the sense that only dyestuffs produced by azo coupling should be used. Rather, the dyestuffs according to the present invention can be produced by any method desired. Thus for example, 2-arylazo pyridine and quinoline compounds which produce particularly valuable colour salts according to the present invention by condensation of the correspondingZ-amino pyridine and quinoline compounds with nitroso aryl compounds, can be used. In particular the p-aminophenyl .azo pyridine and quinoline dyestufis produce very valuable colour salts according to the present invention which can. be obtained according to this method by using p-nitroso dialkyl anilines, p-nitroso diphenylamines or p-nitroso benzyl alkyl anilines. If dyestuifs produced by azo coupling are used, then B for example, can represent the radical of an acyl acetic acid arylamide, an 0- or p-hydroxyaryl or an 0- or p-amino aryl radical, a 3-indolyl radical, a S-hydroxy or S-amino pyrazole radical.

In the preferred p-aminoaryl azo dyestuffs, the amino group can be primary, secondary or tertiary. The substituents of the amino group can be aliphatic, araliphatic, alicyclic, aromatic or heterocyclic. They can be further substituted, as in the oxalkyl, fiuoralkyl, cyanalkyl, alkoxy and phenyl alkyl, the alkylphenyl, alkoxyphenyl, halogen phenyl and the alkylbenzyl, halogen benzyl and alkoxybenzyl compounds. Aliphatic substituents of the amino group can also form hydrogenated rings either among themselves or with an ether atom or with the aromatic radical having an amino group as in the piperidino, the morpholino, the 1.2.3.4-tetrahydroquinoline, the lilolidine, julolidine, and perimidine compounds. The preferred p-aminophenyl radical in the azo dyestufi's preferably, low alcohols.

usable according to the present inventioncan be further substituted as desired within the bounds of the definition, for example by halogen, alkyl, alkoxy, nitro, acylamino, alkyl sulphonyl groups. Monoazo dyestulfs are to be preferred to polyazo dyestuffs.

Alkylating agents suitable for the production of colour I estersor the halogen hydrines of divalent or trivalent alcohols with '2 to 4 carbon atoms can be used.

The monoazo dyestufis usable according to the present invention are reacted with suitable alkylating agents advantageously in inert organic solution, the colour salts formed often precipitating and being isolated by filtration. Liquid aliphatic, cyclo-aliphatic or aromatic hydrocarbons can be used as inert organic solvents, also stable aliphatic or cyclic halogen compounds such as e. g. carbon tetrachloride, tetrachlorethylene, chlorobenzene, dichlorobenzenes or nitrobenzene. If too energetic reaction conditions are avoided the reaction can also be performed in an excess of liquid alkylating agent. The reaction of the azo dyestuffs which are insoluble in water with the alkylating agent is exothermic and generally on the formation of the cyclammonium salt there is a strongly bathochromic change in colour. However, heating of the components to introduce the reaction is almost always necessary, in particular when the reaction is performed in the presence of inert organic diluents. Advantageously an excess of alkylating agent is used. Under energetic reaction conditions any nontertiary amino groups present in the starting dyestutf can be alkylated, but as far as the action of the alkylating agent is concerned, the formation of the cyclammonium salt is the preferred and primary reaction. In some favourable cases the cyclammonium salts can be formed also in alcoholic solution and even in aqueous dispersion in the presence of capillary active non-ionogenic or anion active Wetting and dispersing agents. Due to the good stability of the colour salts according to the present invention, the solvents can also be removed by distilling off, possibly under reduced pressure or by steam distillation. Also colour salts according to the present invention can be obtained from organic solvents which are not miscible with water by extraction with water. The colour salts according to the present invention are purified advantageously by dissolving in water, any starting dyestutf present not going into solution. The aqueous solutions are treated with solid adsorbents such as charcoal -to remove oily impurities and the colour salt is isolated by salting out. The presence of acid hydrogen halide salts of metals of the second sub-group of the periodic system of chemical elements such as zinc chloride or cadmium chloride, is an advantage.

equivalent to the cation, the coloured cation not containing any acid dissociating, salt forming groups such as sulphonic acid or carboxyl groups.

Preferably A represents an N-alkyl pyridinium or N- alkyl quinolinium ring bound in the 2-position to the azo group; B represents a p-aminophenyl radical wherein the amino group can be primary, secondary or tertiary; and X represents a halogen ion or an inorganic or organic anion derived from an acid of hexavalent sulphur. The N-alkyl group of the pyridinium ring can be further substituted, e. g. by phenyl, alkylphenyl, halogen phenyl, or alkoxyphenyl groups in aralkyl substituents or by the hydroxyl group in oxalkyl substituents. X is generally the anion of a strong acid, e. g. a chlorine, bromine or iodine ion, a metho or etho sulphate ion, a sulphate or bisulphate ion, a benzene, halogen benzene or alkyl benzene sulphonic acid ion. However, the strongly basic, coloured cations also form stable salts with weaker acids so that also the radicals of organic acids can be used, c. g.

the anions of acetic acid, formic acid, oxalic acid, lactic acid, tartaric acid; some of the bases themselves are even stable, so that X9 may also represent the hydroxyl ion. Often double salts of the colour salts according to the present invention can be produced with advantage with certain inorganic metal salts and used, in particular the zinc chloride double salts. Thus also more complex anions, for example the chlorozincate or chlorocadmiate ion can be used as the anion X equivalent to the coloured cation.

As can be seen, the uncoloured anion plays a secondary role. The dyestufi? character is determined by the coloured cation. Thus the colour salts according to the present invention can be termed basic dyestuifs. Only, it is favourable for the water solubility, if X represents one of the anions of stronger acids first listed above. Compounds with less good water solubility can generally be dissolved easily by the addition of acids.

In aqueous solution, the dyestuffs according to the present invention dye cellulose fibres mordanted with tartar emetic and tannin, silk, leather and polymeric synthetic fibres containing nitrogen which consist of polyacrylonitrile or are made chiefly from acrylonitrile, for example by mixed polymerisation, generally in very pure shades. The dyeings attained with the dyestufis according to the present invention are often distinguished by very good fastness to light.

The following examples serve to illustrate the invention. The parts are given as parts by weight and the 'temperatures are in degrees centigrade.

The relationship of parts by weight to parts by volume is as that of kilogrammes to litres.

EXAMPLE 1 A solution of 9.4 parts of 2-amino pyridine in 300 parts of abs. toluene is boiled under reflux for 30 minutes in a nitrogen atmosphere with 4 parts of finely pulverised sodium amide. 15 parts of freshly prepared 1-N.N- dimethylamino-4-nitroso benzene are added to the suspension of the sodium salt of 2-amino pyridine so obtained and the reaction solution is boiled for another 3 hours under reflux (see Brown, I. A. C. S. 73, 4608 (1951)). The reaction mixture is evaporated to dryness in the vacuum and extracted warm with 25% acetic acid. While cooling, the acetic acid extract is carefully neutralised with concentrated lye and the precipitated dyestuff is filtered off.

A solution of 2.3 parts of this dyestutf in 100 parts of tetrachlorethane is reacted at boiling temperature for 1 hour with 3.9 parts of dimethyl sulphate in parts of tetrachlorethane. The dyestuff which precipitates on cooling, is then filtered ofi.

The violet dyestulf obtained is dissolved in 200 parts of hot water and again precipitated with 1.5 parts of zinc chloride and sodium chloride from the solution which has been clarified with a little charcoal. The dyestutf dissolves in concentrated sulphuric acid with a yellow and in water with a violet colour. It dyes polyacrylonitrile fibres, mordanted cotton and silk from an acetic acid bath in violet shades which have good general fastness properties.

If, instead of 1-N.N-dimethylamino-4-nitroso benzene, the nitroso compounds listed in Table 1 are used, then similar products are obtained.

Table 1 Dye- Sol- Dyeing on Nitroso compound stuff, vent, Alkylating agent polyacryloparts parts nltrlle fibres 1-N.N-diethy1amlno 2. 6 2.2 pts. p-toluene Violet.

4-nitrosobenzene. sulpbonlc acid methyl ester. l-N-ethyl-N-benzyl- 3. 2 150 3 pts. dimethyl Do.

amino-tnitrososulphate. benzene.

7.2 parts of 2-amino quiuoline are condensed in the presence of 2 parts of sodium amide in toluene as solvent with 7.5 parts of 1-N.N-dimethylamino-4-nitrosobenzene ,in a manner analogous to that described in example 1. ,2.9 parts of the dried azo dyestufi in 100 parts of toluene are then methylated at with 1.8 parts of dimethyl sulphate in 10 parts of toluene. After cooling the reaction mass, the reaction product is filtered off and taken up in 200 parts of hot water, the violet solution is filtered and the colour salt is precipitated, on the addition of 1.5 parts of zinc chloride, with sodium chloride in the form of the zinc chloride double salt. The

,dyestuif dissolves in water with a violet and in concentrated sulphuric acid with a yellow colour.

From an acetic acid bath, it dyes polyacrylonitrile fibres and silk in violet shades which have excellent fastness properties. Water soluble dyestuffs with similar properties are obtained by using the nitroso compounds listed in Table 2. Also instead of 2-amino quiuoline, homologues thereof such as 2-amino-8-methyl quiuoline or 2-amino-4-methyl quiuoline can be used. The colour salts so obtained dye polyacrylonitrile fibres, mordanted cotton, silk and leather in vivid violet shades. In water they dissolve with a violet and in concentrated sulphuric acid with a yellow colour.

All the products obtained according to the above table dissolve in water with a violet and in concentrated sulphuric acid with a yellow colour.

EXAMPLE 3 Following the example of Tschitschibabin (Chem. Zentralblatt 1916, II, 228 and Chem. Zentralblatt 1923, HI,

dine in 50 parts of abs. alcohol are coupled while in- 'troducing carbon dioxide with 7 parts of a-naphtliol. The coupling solution is poured into ice Water and the dye- Whatwe claimis: 1 1 o 1. A dyestufl of the general formula:

Whlch preclpltates 1S purified, by Way of the sodlum the cation part of which is free from acid saflt forming p groups and wherein A represents an N-alkyl pyridinium pat:satire?is.5.2 232 5021222;tastes; it e e a -atom at orms part sai pyri inium ring'=' reprethis d estufr in 150 arts of toluene, the addition bein made within 5 minut s at 120 and the reaction mixtur '10 sergsgp'va'rylene radical? Z an ammo group a e t a" is kept for another 45 minutesat 120. The dyestuif A zzi z E gf g which precipitates after cooling, is filtered ofli, taken up in p I 200 parts of warm water, the solution is clarified with a A ='N" "Z B 6 little charcoal and then the colour salt is precipitated with sodium chloride. The dyestufi dissolves in-concen- 15 the catloll P WhlCh 18 free from 361d Salt t u g trated sulphuric acid with a red brown and in water with groups a Whefem fePlesel'lts an N'alkyl PYrldllllum a yellow brown colour. Polyacrylonitrile fibres, "morhetero g System Whlch 1S bound to the azo group by a danted cotton, and silk are dyed from an acetic acid bath c'atom that forms p f Sald PYfldmlllm 3 Y p in orange shades which have good fastness properties. sents a pphenylene Tadlcal; Z represents an ammo group, A similar dyestuif is obtained if fl-naphthol is used as 20 and X9 represents an amoncoupling component and the amounts of substances given A dyestufi of the g11em1 formula! in the above example are used and conditions described QB e therein are kept. [ATN=N Y ,Z] X

EXAMPLE 4 the-cation part of which is free from acid salt forming (1 wherein A represents an N-alkyl pyridinium 9.4 parts of 4-am1no pyridine are condensed with 15 groups 1" parts of 1-N.N-dimethylamino-4-nitrosobenzene in exactlfqng whlch g to i group by a c'atom that ly the same manner as described in Example land the 32: i g zi gg i g represents pyridyl-4-azo dyestufi obtained is methylated as described regents an anisn p e n ammo group an in the above examples. A water soluble violet colour 2 A d esmfl of eneral formul salt is obtained; it dissolves in concentrated sulphuric y g acid with a yellow colour. From a neutral bath, it dyes 9 silk, mordanted cotton and polyacrylonitrile fibres in violet shades. Similar dyestufls are obtained if other the 621 0 Pa f Ch 18 fr from acld Salt forming nitroso compounds such as 1-N.N-diethylamino-4-nitroso 5 groups and Wherein A represents an I I-alkyl quinolinium or 1-N-ethyl-N-benzylamino-4-nitroso benzene are used. ring which s bound to the azo group in the 2-position of These colour salts dye silk, mordanted cotton and polythe h r g, represents a P-p y i Z r pacrylonitrile fibres also in vivid violet shades. resents an amino group, and X6 represents an anion. EXAM LE 5 5. A dyestuff of the formula:

40 4.7 parts of 3-amino pyridine are dissolved in 50 parts 7 CH of water and 17 parts of concentrated hydrochloric acid 3 and diazotised under ice cooling with 50 parts of N- CI'ZIICM nitrite solution and then coupled in an acid medium with 6.0 parts of dimethyl aniline. After buifering the reaction CH3 7 solution with sodium acetate, the precipitated dyestufi is A d t fi f h formula; filtered off, washed With a lot of water and dried in the vacuum. 2.3 parts of this monoazo dyestuif are dissolved v in 200 parts of chlorobenzene and methylated at 120 a with 1.4 parts of dimethyl sulphate in 20 parts of chloro- Q benzene. The colour salt which precipitates is further 7 Worked up as described in Example 2. It dyes mordanted CH3 a cotton, silkand polyacrylonitrile fibres in red shades which have good general fastness properties. A dyestufi of formula- Also other solvents such as toluene, chloroform or CHz-CHa tetrachlorethane can be used for the alkylation instead of 800cm chlorobenzene. I CH Products with similar properties are obtained'if the monoazo dyestufir's obtained from 3-amino pyridine and \N the coupling components listed in Table 3 below are used.

Table 3 Dye- Sol- Solution colour in- Dyeing on Coupling component stuff, vent, Alkylatmg agent polyaci'yloparts parts nitrile fibres H2O K250400110.

N.N-diethylaminobenzene 2. 54 200 1.4 pts. dimethyl sulphate Red Red. N-ethyLN-benzylaminobenzene. 3.16 250 do .do Do. Phenol 1.9 200 2 ptsi p-tclsutgiie sulphoruc acid Yellow Yellow. 1118 a-Naphtnol 2.5 600 1.7 pts. diethyl sulnbate do Do,

l-amino-3-methylbenzene 2.1 200 2 ptsihp-ltglsitiene sulphonic acid Redorange. Yellow Bigowgiish I118 er. Ta 13. s-hydroxy-s.6-nephtho-1.2.3.4-tet- 3.1 250 1.7 ptsziiethyl sulphate Red .-do Red. g

rahydro pyridine.

7 8 8. A dyestufi of the formula: 2,135,293 Renshaw et a1 Nov. 1, 1938 CH 2,283,220 McNally et a1 May 19, 1942 2,294,380 'Braker Sept. 1, 1942 N: 2,744,105 Barney May 1, 1956 SOOGH: 5 N V OTHER REFERENCES 1 1 Sannders: The Aromatic Diazo Compounds (2nd ed.),

m I 1 V 1949, pp. 78-9. References Cited in the fileof this patent 10 v UNITED STATES PATENTS 2,022,921 Mietzsch et a1. Dec. 3, 1935 

1. A DYESTUFF OF THE GENERAL FORMULA: 